(a) Field of the Invention
The present invention relates to a droplet discharge apparatus. More particularly, the present invention relates to a droplet discharge head and a droplet discharge apparatus that have a gas outlet.
(b) Description of the Related Art
Generally, a droplet discharge apparatus applies pressure to a liquid such that a droplet forms at a tip and subsequently drops therefrom. However, there is a problem that the size of the droplet cannot be reduced below a certain level when the droplet is forced to drop by applying pressure only.
In order to reduce the size of a droplet formed at the tip, the internal diameter of the tip must be reduced. However, the reduction of the internal diameter of the tip causes a problem that the tip is clogged with impurities accumulated therein. Further, even if the internal diameter of the tip is reduced, only reducing the size of the tip is limited in decreasing the size of the droplet since the surface tension of the droplet still remains.
Forces acting on a droplet just before the droplet drops from the tip are gravitational force, changes in the momentum of the droplet, and the surface tension of the droplet.
Here, if the combined value of the changes in the momentum and the gravitational force is greater than the surface tension, the droplet drops. Accordingly, however small the internal diameter of the tip is formed, it is difficult to reduce the size of the droplet below a certain level due to the surface tension.
In addition, it is extremely difficult to maintain a constant amount of the droplet that drops from the tip since the droplet falls instantaneously along with the amount of the change in momentum.
As new fields of application of nanometer-scale microstructures become more widely known, it is most important to provide tiny droplets for manufacturing nanometer-scale microstructures in an accurate manner. However, it is difficult to accurately provide droplets with a prior art.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.